DE3616009C2 - Process for the preparation of optionally substituted phenylchlorothioformates - Google Patents

Description

The invention relates to a process for the production of optionally substituted, phenylchlorothioformates. Phenyl Chlorothioformates are intermediates for drugs and agricultural chemicals very suitable.

It is known that phenylchlorothioformates by reaction a phenolic compound with thiophosgene in the presence of a Hydrogen halide can be produced can. However, since thiophosgene has high toxicity, he requires great care in its handling. Regarding the Risks from accidents, such as leaks, are desirable Storage or transportation of thiophosgene in large quantities to avoid. So there was already a manufacturing process proposed by phenyl chlorothioformates in which sulfur dioxide with a mixed solution consisting of a phenol compound, perchloromethyl mercaptan, an organic Solvent and water, is implemented and then a Hydrogen halide is added. With this However, the process is called phenoxydichloromethanesulfenyl chloride By-product formed, which increases the yield of phenyl chlorine thioformates is reduced.

The object of the present invention is to provide a method for Production of optionally substituted phenylchlorothio to provide formats in which the storage or the transport of thiophosgene in large quantities is avoided and the phenylchlorothioformates in high yield on light and can be manufactured safely.

This task is accomplished by a method of the type mentioned at the beginning Kind solved, which is characterized in that one

• a) sulfur dioxide with a mixed solution consisting of per chloromethyl mercaptan, a chlorinated or aromatic Koh hydrogen and water, at about -10 ° C to room temperature, implements
• b) separating the aqueous layer and
• c) an optionally alkyl-substituted phenyl or a condensed phenol and a hydrogen halide medium in that order to the remaining organic Layer there, giving the concentration of halogen hydrogen elimination agent in the solution at about 5 to 20 Weight percent holds.

The invention is described in more detail below.

Perchloromethyl mercaptan becomes a chlorinated or aroma hydrocarbon and water are given a solution to obtain a mixture, the amount of mercaptan being at least 1 mol, preferably at least 1.1 moles, based on 1 mole of one Phenol compound.

The chlorinated hydrocarbon is, for example, chloro form, dichloromethane or carbon tetrachloride, and the aroma Table hydrocarbon is, for example, benzene, toluene or xylene. It is desirable to have water in an amount of at least 2 moles, based on 1 mole of perchloromethylcaptan use. A small amount of an alkali metal iodide can be added so that the reaction proceeds evenly.

So that the sulfur dioxide reacts with the mixed solution can, sulfur dioxide is either mixed directly into the Solution initiated or a sulfite and concentrated sulfur acid are added to the mixed solution to make sulfur to produce dioxide in the reaction system. In the former case sulfur dioxide is obtained in an amount of 1 to 20 mol to 1 mole of perchloromethyl mercap  tan, used. In the latter case, the sulfite is in one Amount of at least 1 mole based on 1 mole of perchloromethyl mercaptan, and concentrated sulfuric acid in an amount of at least 1/10 mol, based on 1 mol per chloromethyl mercaptan used.

As the sulfite, alkali metal bisulfites such as sodium hydrogen sulfite or potassium hydrogen sulfite, alkali metal sulfites, such as sodium sulfite or potassium sulfite, ammonium hydrogen sulfite and ammonium sulfite can be used.

Next, the aqueous layer from the reaction mixture removed, and to the remaining organic Layer become a phenolic compound and a halogen water given off in this order.

Unsubstituted phenols, alkylsub substituted phenols, such as methylphenol, ethylphenol or tert-butylphenol, and condensed phenols such as β-naphthol or 5,6,7,8-tetrahydro-2-naphthol can be used.

Inorganic hydrogen release agents can be Bases, such as alkali metal hydroxides, alkaline earth metal hydroxides or alkali metal carbonates, as well as organic bases, such as Triethylamine, pyridine, quinoline or isoquinoline used will. The hydrogen halide is in one Amount of 1 mole, based on 1 mole of phenol, used.

The hydrogen halide cleaving agent is usually described in dissolved form used. The concentration of the halogen water splitting agent in solution is very important for that Yields of phenyl  chlorothioformates. The use of a solution that High concentration of hydrogen halide contains, produces diphenylthiocarbonate as a by-product and reduces the yield of phenyl chlorothioformate. Other on the other hand, when using a solution that Hydrogen halide in a too low con contains a large capacity reaction vessel needs what is disadvantageous. That is why the concentration lies of the hydrogen halide in the solution about 5 to 20% by weight.

The reaction temperature is about -10 ° C to room temperature.

The reaction time is usually within about 10 hours.

Phenylchlorothio formate in high output in an easy and safe way will hold.

The following examples illustrate the invention.  

example 1

In a 1 l three-necked flask equipped with a Stirrer, a thermometer and a 300 ml dropping funnel ter, 150 g of perchloromethyl mercaptan, 240 ml Carbon tetrachloride, 240 ml water and 1 g potassium iodide registered. The flask was cooled with ice.

150 g of sulfur dioxide was added to the above solution initiated with stirring. The temperature inside the Flask was kept at 0 ° C to 10 ° C.

Then the water layer became from the reaction mixture removed, and to the remaining organic layer 90 g of 3-tert-butylphenol and 290 ml a 10% aqueous sodium hydroxide solution in the given this order. After the addition was complete stirring continued for a further 2 h. After graduation the organic layer of the reaction Separated reaction mixture and a distillation set to 130 g of 3-tert-butylphenylchlorothioformate to obtain. The yield of this product was 94.8%, based on 3-tert-butylphenol.

Control example 1

In a 1 l three-necked flask equipped with a Stirrer, a thermometer and a 300 ml dropping funnel ter, 60 g of 3-tert-butylphenol, 75 g of perchlor methyl mercaptan, 240 ml carbon tetrachloride, 240 ml Water and 3 g of potassium iodide entered. The piston was chilled with ice.

100 g of sulfur dioxide was added to the above solution initiated with stirring. The temperature inside the Flask was kept at 0 ° C to 10 ° C.  

Then the water layer was removed from the reaction mixture and the remaining organic layer dropwise 42 ml of a 40% aqueous sodium hydroxide solution given.

After the addition was complete, stirring was continued for a further 2 h continued. After completion of the reaction, the organic Layer separated from the reaction mixture and a distilla tion exposed to 46.6 g of 3-tert-butylphenylchlorothioformate to obtain. The yield of this product was 51% based on 3-tert-butylphenol.

Examples 2 to 5

A phenolic compound and other substances as in Table 1 were shown in the same device as in Bei game 1 was used, a reaction under exposed to the conditions of the invention as shown in Table 1, which correspond to the same as in example 1, to the corresponding phenyl chlorothioformate products, as in Table 1 shown.

The results are shown in Table 1. The yield at Phenol chlorothioformate in% is based on the phenol used pulled.

Example 6

In a 1 l three-necked flask equipped with a Stirrer, a thermometer and a 300 ml dropping funnel ter, 160 g of perchloromethyl mercaptan, 210 g of Na trium hydrogen sulfite, 200 ml carbon tetrachloride, 250 ml of water and 2 g of potassium iodide entered. Of the Flask was cooled with ice.

25 ml of concentrated sulfuric acid was added dropwise added to the above solution and ge over 10 h stirs. The temperature inside the flask was at 0 ° C during the addition and then at room temperature held.

The water layer was removed from the reaction mixture and the remaining organic layer were added dropwise 80 g of 4-methylphenol and 320 ml a 10% aqueous sodium hydroxide solution in given this order. The stirring was over continued for another 2 h.

After completion of the reaction, the organic Layer separated from the reaction mixture and one Exposed to distillation to 110.6 g of 4-methylphenyl to obtain chlorothioformate. The yield of this Product was 80% based on 4-methylphenol.

Control example 2

In a 1 l three-necked flask equipped with a Stirrer, a thermometer and a 300 ml dropping funnel ter, were 85 g of 4-methylphenol, 147 g of perchloromethyl mercaptan, 290 g sodium bisulfite, 150 ml di chloromethane, 250 ml of water and 3 g of potassium iodide carry. The flask was cooled with ice.  

3.5 ml of concentrated sulfuric acid became drop-white se added to the above solution and over 25 h touched. The temperature inside the flask was at 0 ° C during the addition and then at room temperature kept.

The water layer became from the reaction mixture removed, and to the remaining organic Layer was added dropwise 315 ml of a 10% given aqueous sodium hydroxide solution. Stirring was continued for another 2 hours.

After completion of the reaction, the organic Layer separated from the reaction mixture and subjected to distillation to 85.2 g of 4-methyl to obtain phenylchlorothioformate. The yield this product was 58.0% based on 4-methyl phenol.

Examples 7 to 10

A phenolic compound and other substances as in Table 2 was shown in the same reaction vessel as used in Example 1, a reaction under the conditions like they are shown in Table 2. There were the same measures according to the invention as carried out in Example 2, around the phenylchlorothioformate shown in Table 2 get products.

The results are shown in Table 2.

Claims (2)

1. A process for the preparation of optionally substituted phenylchlorothioformates, characterized in that

• a) reacting sulfur dioxide with a solution mixture consisting of per chloromethyl mercaptan, a chlorinated or aromatic hydrocarbon and water, at about -10 ° C. to room temperature,
• b) separating the aqueous layer and
• c) an optionally alkyl-substituted phenol or a condensed phenol and a hydrogen halide release agent are added in this order to the remaining organic layer, the concentration of the hydrogen halide release agent in the solution being maintained at about 5 to 20 percent by weight.

2. The method according to claim 1, characterized in that one in a) a small amount of an alkali metal iodide for solution mixture there.